chemistry- reversible reactions, industrial processes and important chemicals

what is a reversible reaction

• a reaction which occurred in 2 directions

• the products can react to form the original reactants

For A+B {} C+D which are the products for the forward reaction and which are the products for the backwards reaction

• forward C+D

• backwards A+B

how can the direction of a reversible reaction be changed

by changing the conditions

• pressure

• temperature

• concentration of reactants or products

if the forward reaction is exothermic, will the backwards reaction be endothermic or exothermic

endothermic, the same amount of energy is transferred

what is the reaction in the Haber process

Nitrogen + Hydrogen{} Ammonia

N2 +3H2 {} 2NH3

what can ammonia be used for

to produce nitrogen- based fuels

where can nitrogen and hydrogen gas be obtained from

Nitrogen: from the air

Hydrogen gas: natural gas or other sources

what are the conditions required for the haber process

• high temperature (450 degrees)

• high pressure (200 atm)

• iron catalyst

what happens during the Haber process

• purified gases passed over iron catalyst

• some nitrogen and hydrogen reacts to form ammonia

• some ammonia breaks down into nitrogen and hydrogen( because reaction is reversible

• Mixture is cooled, ammonia liquifies and is removed

• remaining nitrogen and hydrogen recycled

what does it mean for the Haber process to be in dynamic equilibrium

forward and backward reaction happens at a consent rate once equilibrium is reached

in which way does the equilibrium shift in the Haber process when pressure is increased? why?

equilibrium shifts to the right. the total number of moles of gases is fewer on the right

the forward reaction of the Haber process is exothermic. How can the conditions be changed to produce more ammonia

by lowering the temperature, the forward reaction is favoured

what are the disadvantages of using low temperature and very high pressure

low temperature: slower rate of reaction

high pressure: requires high energy

what are the two things aimed to be maximised when choosing the conditions of the Haber process

rate of reaction and yield of ammonia

how can the presence of ammonia be tested

most red litmus paper will turn blue as ammonia is alkaline

how can the process of ammonium ions be tested? what is the ionic equation for this reaction?

• add solution containing hydroxide ions

• test for ammonia gas

• NH4+ (aq) + OH- (aq) } NH3 (g) + H2O (i)

what kind of reaction are used to make nitrogenous fertilisers from ammonia

neutralisation reactions

what are some examples of nitrogenous fertilisers? what are their molecular formulas?

ammonium sulfate- (NH4)2 SO4

ammonium nitrate- NH4 NO3

how can ammonium slate be formed form sulfuric acid?( 2 different ways)

• ammonia + sulfuric acid } ammonium sulfate

• ammonium hydroxide + sulfuric acid } ammonium surface + water

what are the 2 ways used to form ammonium nitrate from nitric acid

• ammonia + nitric acid } ammonium nitrade

• Ammonium hydroxide + nitric acid } ammonium nitrate + water

what are the advantages of using fertilsers

• increases crop yield and growth

• increases profit for farmers

what are the disadvantages of using fertilisers

• eutrophication when fertilisers are washed off into rivers and lakes

  • increase of nitrate and phosphate in water encourages algae growth

  • algae bloom blocks sunlight from water plants underneath

  • water plants die and are broken down by bacteria

  • oxygen is used up by bacteria, killing other living organisms in the water

• many stages in manufacture

• changes of pH in the soil

• can cause baby blue syndrome

what does it mean for cultures acid to be a strong acid

it completely dissociates in water and releases H+ ions

what is the molecular formula and the structure of sulfuric acid

what is the contact process

the manufacture of sulfuric acid

what is the first step of the contact process

Silver is burned in the air and reacts with oxygen to form sulfur dioxide

what is the second step of contact process

sulfur dioxide reacts further with oxygen to form sulfur trioxide

• reversible

• catalyst: vanadium (V) oxide(V2O5)

• temperature: 450 degrees

• pressure: 2 atm

what is the third and final step of the contact process

sulfur trioxide reacts with water to form sulfuric acid

what is the reversible step in the contact process and what are the conditions for this reaction

the second step

• catalyst: vanadium (V) oxide( V2O5)

• Temperature 450 degrees

• Pressure:2atm

what are the uses of sulfuric acid

• mostly used to make fertilisers

• manufacture of chemicals ( HCI, HNO3, sulfate salts, synthetic detergents, fibers, plastics, dyes, and pigments, explosives and drugs )

• petroleum refining: waging impurities out of gasoline and other refinery products

• processing metals

• manufacture of rayon which is used as electrode in the lead- acid storage battery

what does a dehydrating agent do

removed water form other compounds

how does concentrated sulfuric acid act as a dehydrating agent with sugar

• concentrated sulfuric acid removes 6 water molecules per glucose molecule

• highly exothermic reaction

• water molecules released as steam and a black mass of carbon forms

what change can be observed when concentrated sulphuric acid act as a dehydrating agent on hydrated copper(III) sulfate

blue crystals ( hydrated copper sulfate) } white powder ( anhydrous copper surfate)